The first Chrome version that received this new engine is Chromium 10.0.605.0. Google justified the JavaScript update with what the company calls "Crankshaft", a new compilation infrastructure for the V8 JavaScript VM. There are some "aggressive" optimizations that boost the benchmark score in V8 by about 50% in our tests and up to 100% in some individual tests, according to Google.

The new browser comes on the heels of the announcement of Chrome OS earlier today, which is closely tied to Chrome and relies on Chrome as a fast browser. However, we also remember that Microsoft has made some pretty impressive improvements with IE9 and the latest Platform Preview 7, which was actually faster in the Sunspider benchmark than any other browser.

ConceivablyTech has posted some benchmark numbers that indicate that Chrome is now faster than IE9 PP7 at least on one of their platforms. But it seems that Microsoft and Google are now tied up in a JavaScript battle that could last a few months. When was the last time a Microsoft browser was actually competing for first place in a browser speed race?